This relationship is to provide additional information for a particular lane of a Way, which might be a bus lane, a cycle lane, a footway, a 2+ car lane etc. The geometry of the lane will be defined by the associated Way (with an implicit or explicit offset applied). The lane_ref tag and lane_type tage are the only required elements.

The lane_ref tag identifies which lane out of a number this one is and their needs to be a way to relate this back to a specific lane on the highway. A lane-spec tag containing a string might work, see below for the detailed proposal.

There are other optional tags, all of which over-ride the values of the same tag in the Way.

In some cases it will be necessary to use a 'composite tag' containing both a Validity Period and an override value for one or more other tags (for example for a bus lane that is only between 7am and 10am, in which case the lanetype would be overridden)

Tags

The lane_ref relates to a lane order given in the Way, ideas about how to implement this would be welcome

highway

cycleway/footway/2carlane/buslane

to define what sort of lane it is

offset

offset in meters from the next innermost lane

...

oneway / width / hgv=yes/no motorcar=yes/no bicycle=yes/no surface

any other tag

Members

There is probably only one member, which is the Way to which the Lane is attached. It would also be possible to associate a couple of nodes to denote a part of the Way to which this feature relates, but that may be over-complicating the feature for the time being.

Way

the Way to which this Lane is attached

Just a quick question. If there is only one member, then surely this tag would be better going on the way, rather than creating a new relation type? Richard B 20:20, 30 October 2007 (UTC)

Identifying the Lanes to the Way

How is each lane located on the road itself?

How about tag lane_spec associated with the Way. Each element of the lane_spec would consist of a letter to indicate the default type of the lane. An implied number would be associated with the lane, so the left most carriageway would be h1 and the leftmost pavement would be p1.

A road with a single car lane in either direction and no pavements would be h1!h2 (where the ! indicates the road centreline). Here are a set of examples.

In some cases the lane relationship would not be required, as all the relevant information would be in the lane_spec. In other case, where the lane has a width, or is two way not the default oneway or where the attributes change during the day then a relationship will be required.

lane_spec

description

h

single track road

h!h

one lane each direction, no pavements

ph!hp

one lane in each direction, pavements both sides

ph!h

one lane in each direction, pavements one sides

sh!h

one lane in each direction, shared use path one side, pavement other side

hh!hh

two lanes each direction, no pavements

bh!hh

two lanes each direction, outside lane in forward direction (driving on the left side assumed) is a bus lane, no pavements